cathyvv, some newer zigzag machines come with two plates with a needle hole. The one with a wider slotted opening is for zz stitching and the small circular one is good for quilting or other straight stitching.
Leaders and enders? I wish I'd known about them when I was trying to quilt with my Elna. She is a very hungry machine and ate lots of narrow corners. My vintage Singer 301 is a SS, so I don't need the leaders for that reason. I do use a few to save thread tails if I can't chain piece.
My 13 year old GD made her first quilt here last week. My son says she can't bring the machine home until she can unjam it. Because she used leaders and enders, it never once jammed - not even one nest. With her leader, she could concentrate on her 1/4", not holding threads. She reused her little squares. Her piecing is near perfect. When we measured the three spots to average for the first border, the measurements were all the same, both the length and width. I think the leaders and enders helped.